Electrical connectors



Nov. 12, 1963 H. H. Essl-:R

ELECTRICAL CONNECTORS 2 Sheets-Sheet 1 Filed Nov. 5, 1961 f/ #fior/refs'.

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l H. H. ESSER ELECTRICAL CONNECTORS Nov. 12, 1963 2 Sheets-Sheet 2 Filed Nov. 3, 1961 INVENTOR.

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United States Patent e '3,1 lil-,755 Patented Nev. 12, 1963 3,110,755 ELECTRICAL CONNECTGRS Harold H. Esser, Chicago, Ill., assigner to Ideal Industries, Inc., Sycamore, Ill., a corporation of Delaware Filed Nov. 3, 1961, Ser. No. 150,859 7 Claims. (Cl. 174-87) This invention is in the field of electrical connectors and is concerned with -a type of insulated connector adapted to be iitted on the stripped ends of the wires and held there lby pressure, either externa-l or internal.

A primary object of my invention is an insulating connector of the cap type which fonms a pressure fit with the stripped ends of electric wires.

Another object is a preinsulated crimp connector which does not require the electrician to twist the stripped ends of the -wires together before applying the connector and crimping it.

Another object is a connector of the above type formed of a ystiiiiy flexible plastic which is capable of being deformed in response to crimping pressure without cracking or rupturing.

Another object is a connector of the above type having a crimpable shell or sleeve on the outside.

Another object is a connector of the above type having a thread form in the interior which may be crimped.

Another object is a connector of the above type having interfitting conic members defining a compression cavity.

Another object is 'a connector of the above type which has a jam -or swaging type action to hold the wires in.

Another object is a preinsulated crimp connector which is crimped from the inside.

Another object is a connector of the above type having an outer crimping band.

Another object is a preinsulated crimp connector which is self-tightening.

Other objects will appear from time to time in the ensuing specilieation and drawings in which:

FIGURE 1 is `a vertical section through one form of my invent-ion;

FIGURE 2 is a vertical section through a modified insert usable in the FIGURE l connector;

FIGURE 3 is like FIGURE 1 showing the connector after it has been crimped;

FIGURE 4 is a vertical section through a further modi- 'fcationg FIGURE 5 is -a vertical section through another form;

FIGURE 6 is a front View of a ,connector of this type, on a reduced scale;

FIGURE 7 is a top View of FIGURE 6;

FIGURE 8 is a top View of a modified form;

FIGURE 9 is a top View of a further modificati-on;

FIGURE 10 is a Vertical section, like FIGURE l, of a further modification;

FIGURE 1l is a vertical section through an additional modification;

FIGUTRE 12 is a vertical section through a further modification showing the connector secured on the stripped ends of the Iwires; and

FIGURE 13 is a vertical section through still a further modification.

In FIGURE l, a connector has been indicated generally at 10 which includes a cap or shell 12 which may be 'made of tan insulating material, for example ny-lon or the like. The cap may have a flared-out ski-rt 14 with a generally open end 16 and closed at the other end by an end wall 18 which is preferably integral with the side wall of the cap. 'Ihe top portion 20 of the cap is shown as generally cylindrical, but this is not necessary.

I position an insert Z2 in the cap which, in this case, is shown as having a Igenerally cylindrical exterior. The

upper portion of the bore of the Icap may also be generally cylindrical so that the insert fits smoothly inside of the cap. It may be held in place Iby gluing or by a shrink iit or otherwise. Be that as it may, the sleeve has an fopen interior defining a threaded lbore 24 and, as shown, I may use a continuous thread, either single or multiple start, which extends from one end of the sleeve to the other. While I show the top of the sleeve open and yonly closed by the end iwall 13 `of the cap, it should be understood that the sleeve may 'bottom against an integral closed wall, if desired.

In FIGURE 3, I show what may be considered the same connector except that external pressure has been applied radially inwardly to the generally cylindrical portion 20 in the area surrounding the insert across a suitable axial extent thereof, as at 26 in FIGURE 3, and on each side to deform .both the outside o-f the cap and the insert inwardly. I prefer that the pressure be applied by a suitable crimping tool at areas on opposite sides of the insulating sleeve, preferably li apart, but there might be three such areas, 120 apart or otherwise, Be that as it may, -the pressure is suitably applied and is of such a force and intensity that it will deform the cap and the insert inwardly somewhat.

The stripped ends of the 'wires to be connected have first been inserted up in the cap, then the cap has been turned down on them. The operator merely bunches the wires together and then turns the cap down on them in a rotary or screwing type action with the helical bore 24 of the insert causing the hunched wires to be twisted during such action. This automatic twisting action relieves the operator of the time consuming and inefficient task of twisting the wires together by hand after he has lbunched them before he slips a crimp sleeve over them.

To make this possible, a helix form Vmust be defined or positioned in the bore of the cap which will twist the wires when the cap is screwed down on them after the operator has bunched them. Also, the helix formation should be defined by an insert, preferably of metal, which will take a permanent set when crimping pressure has been applied to the outside of the cap.

Also, the helix formation should be surrounded by an insulating material which will not rupture, crack or break when crimping pressure is applied. For example, the material of the cap may be `a stiiy flexible plastic, such as nylon or the like. It should not be a rigid thermosetting plastic, such as Bakelite, one of the phenolics, porcelain, etc. In addition, I prefer that the insulating material also assume a semi-permanent set when crimped, as Shown in FIGURE 3, so that the insert and shell conform to each other after a crimp connection has been made. Incidentally, in FIGURE 3 I have not shown the wires in the thread formation, but it should be understood that the wires are iirst turned into the bore of the cap and then the crimp is applied. But in FIGURE 3 I have eliminated the wires for clarity.

In the forms shown in FIGURES l, 2 and 3, crimping pressure is applied .to the outside, preferably between the ends of the insert, so that a configuration results which flares out at each end, as at 28, with a narrow portion or throat 301 defined in the center. I-t will be understood, of course, that when crimping pressure is applied at only two points, for example, on opposite sides of the cap, lthe helix formation in the bore of the insert, while narrow in one plane, as shown in FIGURE 3, will be flattened or widened in the other, at to FIGUR-E 3. Be that as it may, the helix formation presents a teethlike interior which, when compressed into the Wires by the crimping action, will tightly imbed itself in the surface of the wires and will firmly lock the Wires in the connector.

In FIGURE 2, I have shown a slightly modified form e of insert 32 in which the thread formation 34 is somewhat discontinuous or interrupted. It should be understood that the thread formation does not have to be continuous to acquire the automatic twisting action referred to above and the joint acquired after crimping will be just as eliicient.

In FIGURE 4, I have shown a modified form in which the outer shell or cap 36l is shown as generally uniformly tapered from one end to the other with the small end being closed by `an integral end wall 38. The same is true of the insert 401, which in this case is shown with a continuous thread 41 like the FIGURE 1 lform. In this form, I may have a continuous or interrupted abutment or ledge 42 a suitable distance down inside of the cap so that the skirt portion 44 extends beyond it. It will be noted that the inser-t at its small end has less diameter than the inside of the abutment 42. but greater at the large end. Thus, the insert may be wedged in past the abutment or ring and, assuming the cap is of a stifliy flexible plastic, the insert will snap into place when fully seated and Iwill be tightly held, depending upon the dimensioning.

A connector of this type can also be crimped from the outside in an area surrounding the Iinsert, for example, generally at t6. In addition to the shoulder or ring 42, I may glue, press fit or otherwise hold the insert in the cap. The material of the Iinsert and cap may be the same as described in connection with FIGURES 1 and 3.

In FIGURE 5, I show a further form in which the cap, as in the case of FIGURE 4, is generally tapered from end to end and defined by a side wall 48 opened at the large end at 50 and closed at the small end by an integral end wall 52. In this case, the thread forming element is in the form of a coil or spring 54 which is of a size or proportion such that it conforms more or less to the inner `surface of the cap with the small end S6 of the spring hitting the closing end wall and the large end 53 stopping a substantial distance cfrom the open end 56 of the cap. In this case, I may use a ring or washer 60 which may have a plurality of teeth around its outer edge, as at 62, such that when the washer is forced up into the cap, the teeth will imbed themselves yby digging into the side wall so that they cannot then be easily forced out. In a sense, the washer locks itself in place `and holds the coil up in the cap. The turns of the coil may be somewhat closely spaced or slightly separated, as shown in FIGURE 5. I may also position a crimping ring or outer shell 64 around the outside of the cap bounding the portion surrounding the coil. The ning in this case may be metal or otherwise and it should be noted that -I have tapered it somewhat to conform to the outside of the cap, but it might be more cylindrical. Also, a retainer or retaining means could be used. This ring or outer shell may be used if the material of the cap is not such that it will hold its distorted or crimped condition after it is compressed. The same is true of the coil 54. In this case, crimping pressure will Ibe applied through the sleeve or ring 64 which will hold whatever nal shape it has to thereby hold the somewhat more flexible cap and coil firmly imbedded in the stripped ends of the wires. As in the previous form, the stripped ends of the wires do not need to be twisted together, lbut only hunched, and the cap can be screwed down on them. The thread formation in the interior 4will automatically twist the wires. The coil 54- may be held by a continuous shoulder or ring, such as shown in FIGURE 4, and Ithe form retaining ring or shell 64 in FIGURE 5 may be used with either the FIGURE 1 or the FIGURE 4 form or both.

While I have shown the cap in FIGURE 1 with a cylindrical top and a -ilared out skirt toward the bottom and a completely tapered cap `in FIGURES 4 and 5 generally uniform lfrom. end to end, it should be understood that it may be otherwise and the precise details of form and dimensioning are not now considered important. For example, in FIGURES 6 and 7 -I show the exterior of a cap Il e which more or less follows the FIGURES 1 and 3 form 'with the top 166 generally cylindrical and the skirt somewhat flared out, as at 68. :In this case, the skirt has been made generally circular, as shown in FIGURE 7, and may have a number of ribs '70 arranged axially or otherwise on the outside to aid the operator in turning the cap down on the stripped ends.

While I have shown the skirt as generally cylindrical with ribs to aid turning, it should be understood that any of the previous forms may be made with a somewhat square skirt, as at 72 in FIGURE 8, or a rectangular one, as at 74 in FIGURE 9. rlf'he point is that the various skirts of the `different forms may be differently shaped depending upon the particular application. The important point through all of these forms, however, is that the operator does not need to 4twist the ends of the wires together before the crimp sleeve is slipped down over them. Further, the sleeve already has its insulation applied which is commonly known as la preinsulated crimp', Prior to` my invention, in all preinsulated crimp connectors, the stripped ends of the wires have to be bunched and twisted together by the electrician before crimping.

In FIGURE lll, I showy a variant form'in which the cap '76 is shown as tapered lfrom a generally open Yend Eli to receive the stripped Vends of the wires, indicated generally at l82, toa generally closed end S4 which, in

this case, is shown as the small end, formed integrally Y with the side wall of the cap, bu-t it might be otherwise. I position an inner metal cup 36 inside of the insulating cap which may also have a closed end wall 88 at its small end or it might be open in the form of a sleeve. In any event, the inside of the cup is somewhat tapered, opening outwardly as shown in the drawings, and an insert 90, also shown as tapered, is adapted to be forced into the inner cup to trap and hold the wires. The exterior of the in- .sert has a generally frusto-couic configuration and a plurality of concentric barbs or rings 92 are disposed around the surface of the insert so that when the insert is forced into the bottom of the cap, the barbs will bite into the wires. It will be noted that the included angle of the insert is roughly the same as or on the onder of the ineluded angle of the cap and cup, but they might vary somewhat. Any suitable tool may be used to force the insert deep into the cup after the stripped ends of the wires have been inserted, or it may be done by hand, and the material of the cup and insert may be such that they will mesh and stick. The material of one may be harder than the otherso that it will bite, but lthis is optional.

In FIGURE 1l, I have shown a further variation in Iwhich the cap 94l has a sleeve 9e positioned against the otherwise closed end 9S. In this case, the sleeve is doubled back `on itself -to define an inner bore portion ltltl and an :outer skirt 102. Between them they define what you might term a continuous circumferential trough ltlvt. A suitable opening 166 in the end wall may provide a passage for a stem w8 which carries an enlargement or a wedging element llltl. It Iwill be noted that the wedging element is positioned generally in the bore of the sleeve and the stem may be long enough and suitably slraped `on its outer end so that it may be pulled, either by hand or by a tool, to force the wedging element Il@ up into the bore, thereby swaging the inner bore or sleeve 106! outwardly to` trap the stripped ends ofthe wires, indicated generally at 112, between the bore and the outer skirt. f

The material of the doubled back sleeve or insert' should be such that the wedging element, without too much difficulty, can force the bore outwardly and completely trap the stripped ends of the wires in the trough. In this regard, the inner surface of the trough may be knurled, barbed or otherwise formed so that 'when the trough is closed against the surface of the wires, the knurls or irregular formation will bite into the wires to rigidly hold them. Further, the doubled back sleeve may be glued in the cap, held by a shoulder such as in FIGURE 4, or otherwise secured so that it will not come out of the cap. Also, the stem and wedging element may be made from ya non-conducting or insulating material, if desi-red. I may provide a reduced yportion o-r neck 114 between the wedging element and stem so that after a connection has been made with the wedging element fully pulled up into the doubled back sleeve, the stem may be broken-off. In this regard, the dimensioning should be such' that the reduced portion will come approximately to the opening 106 so that the shoulder 116y will fully and tightly close the :opening 106 after the stem is broken oit. Also, the :stem may extend out the open end of the cap, instead of going through the end wall. And I may use either type of stem in the FIGURE form.

In FIGURE 12, I show a lf-urther variation in which the cap 11S has an hourglass appearance with a reduced portion or throat 120 with a liaring skirt 122 below it and 1an enlarged top 124 above it. A shell or cup 126 may be positioned in the insulating cap and it will be noted that it conforms more or less to the cap and also has a reduced portion or throat 128. I may position an inse-rt 139 up inside of the cap which is similar to the insert shown in FIGURE 10. In this case, the insert, as in the oase yof FIGURE 10, is generally frusto-conic and may have a series of rings or barbs i132 running from one end -to the other. The large end of the insert, which is toward the top or closed end of the cap, has a diameter which is greater than the diameter of the throat 128 so that the insert -will not come out.

The insert may be otherwise free in the top of the cap except that it cannot get out. The Stripped ends of the wires, indicated generally at 134, are inserted up into the cap and will stop around the insert. Thereafter, I may lapply pressure against the top of the end wall, as at 136, to defo-rm the end wall inwardly, as shown in FIGURE 12, thereby driving the insert down to wedge it and the stripped ends of the wires in the throat. I may have a ring of metal or otherwise, as at 138, around the cap above the throat to aid in holding the side Walls against expansion when the insert is driven into the throat.

In the FIGURE 12 form, I may use a special tool to hold the connect-or at and around the throat at the same time that ian axial thrust as applied to the end wall to create the indent at 136, thereby driving the wedge into the thro-at.

In FIGURE 13, the cap may be shaped generally the same as in FIGURE 12, except that the end wall 140 is not indented. In this case, the insert 142 is drawn down and wedged into Vthe throat by a stem '144 which projects out through the thro'at and out through the open end of the cap. I may provide a reduced portion or neck 146 in the stem so that after a connection has been made, the stem may be broken orf.

In connection wvith the use of a stem, such as shown in FIGURES 11 and 13, it should be understood that a stem may also be used in FIGURES l0 and 12. For example, I may have a stem projected up inside of the cap in FIG- URE 10 and connected to the insert. `Or I may have a stem project down through a suitable opening in the end wall 84 of 4the cap in FIGURE 10, like in FIGURE 1l. The same is true in `FIGURE 12. I may have the stem come from either direction, through the open end of the cap, as in FIGUR-.E 13, or through an opening in the top or closed end wall of the cap, to drive the insert into the throat, as in FIGURE 11. In FIGURE 11, the wedge 110 may have barblike rings, as in iFIGURE 10.

The use, operation and function of my invention are as follows:

I provide what is commonly termed Aa preinsulated crimp connector, which means that the connector ferrule or sleeve is fully insulated prior to being crimped. In a normal crimp connection the sleeve is slipped over the stripped ends of the wires and crimped. Then an insulator is put around the connection or joint.

But in this invention the metal sleeve or coil, as the case may be, is already insulated. f

In the form shown in FIGURES 1 -through 5, the coil yformation inside of the insulating cap is such that it will automatically perform the twisting function as the cap is `screwed down on the stripped ends of the wires. Thus the operator does not have to twist the wires together before he slips them into a metal sleevie. This has many advantages over a conventional crimp connection in that the operator eliminates two steps, iirst, twisting the wires together and, second, applying the sleeve land insulator separately.

In the forms shown in FIGURES 10 through 13, the connection is made by a wedging action. In a sense, I provide intertitting parts, both of which are frusto-conical, to deiine a generally frusto-conic compression chamber or cavity between them. To make the connection, the stripped ends of the wires are positioned in the cavity and one part is driven toward the other. In the four forms shown, in FIGURES` l0 through 13, the inner part or insert is driven into the outer part which is the cap or cup or sleeve, as the case may be. The barbs or ridges shown in lFIGURES 10, l2 and 13 may in `certain circumstances be eliminated or reduced. But in most applications I lind them of distinct advantage since they do tend to bite into the wires and make a -iirm wedge connection. In the yform shown in FIGURES l2 and 13, lthe joint is self-tightening and any tension applied to the connection merely drives the wedge or insert tighter into the throat. The compression between the inner and outer parts may be made by hand or by a suitable hand tool, if desired. The crimp `applied to the connectors, shown in vFIGURES ll through 9, may be done by 1a suitable hand tool or a bench or mechanical crimping device.

While I have shown and described the preferred form and suggested several variations and modifications of my invention, it should be understood that suitable additional modifications, changes, substitutions and alterations may be made without departing from the inventions fundamental theme. I, therefore, wish that the invention be unrestricted, except as by the appended claims.

I claim:

1. In an electrical connector, a cap having a generally cemtral bore closed at one end and open at the other and made of an insulating material, generally truetoconic interlitting parts in the bore, one smaller than the other and generally concentrically arranged 'with the small end of both in the same direction deiining between them an annular compression cavity, at least one of the parts being free to move in a direction toward the other in response to an axial non-rotary thrust to reduce the volume of the compression cavity to thereby wedge and hold the stripped ends of electric wires inserted in the compression cavity, the interlitting parts being defined by a sleeve doubled back on itself and positioned in the lcap defining a trough opening toward the open end of the cap with a generally central bore, the trough being constructed to receive the `stripped ends of the Wires, and a wedging element in the central bore of the doubled back sleeve adapted, in response to an axial thnust directed to drive the wedging element through the bore, to swage the bore outwardly thereby closing the trough and trapping the ends Iof the wires between the two sides of the doubled back sleeve.

2. The structure of claim 1 further characterized in that the wedging element has a stem extending through the bore of the doubled back sleeve, and an opening in the otherwise closed end wall of the cap through which the stem extends adapted to be manually pulled to drive the wedging element into the bore of the doubled back sleeve.

3. The structure of claim 2 further characterized by and including a reduced section between the stem and wedging element so that after the connection is made, the 4stern may be broken off.

4. The structure of claim 2 further characterized in that the stem and Wedging element are made of an insulating material. t

5. In an electrical connector, a cap having a generally central bore closed at one end and open at the other yand made of an insulating material, generally frustoconic interfitting parts in the bore, one smaller than the other and generally concentrically arranged with the small end of both in the same direction defining between them an annular compression cavity, at least one of the parts being free to move in a direction toward the other in response to an axial non-rotary thrust toA reduce the volume of the compression cavity to thereby wedge and hold the stripped ends of electric wires inserted in the compression cavity, the outer part of the intertti'ng parts being generally `frusto-conic and disposed in the cap bore, smallend toward the open end of the cap, with the cap conforming generally to the exterior of the outer part, thereby defining a reduced section between the ends of the cap, and a generally fnusto-conic wedge element constituting the inner part disposed within the outer part and having a maximum diameter at its large end greater y between the end Wall `of the cap andthe reduced portion 25 than the minimum diameter of the outer part `at the reduced section.

6. The structure of claim 5 further characterized by and including `a stem connected to the small end of the inner part tand extending out through the reduced section and open end of the cap so that it may be manually pulled to reduce the volume of the compression charnher and wedge the stripped ends of the Wires between the two parts. I

7. The structure of claim 6 further characterized by and including a reduced section` between the stem and inner par-t such that after `a connection has been made, the stem may be broken off and removed. v

References Cited in the le of this patent UNITED STATES PATENTS 399,465 Bainbridge Mar. 12, 1889 1,700,985 ltasper Feb. 5, 1929 2,714,197 Wharton et al July 26, 1955 2,729,695 Pierce Jan. 3, 1956 2,802,257 Holtzapple Ang. 3, 1957 2,870,239 Ustin Jan. 20, 1959 2,910,525 yFrank Oct. 27, 1959 FOREIGN PATENTS 299,802 Italy Aug. 17, 1932 

5. IN AN ELECTRICAL CONNECTOR, A CAP HAVING A GENERALLY CENTRAL BORE CLOSED AT ONE END AND OPEN AT THE OTHER AND MADE OF AN INSULATING MATERIAL, GENERALLY FRUSTOCONIC INTERFITTING PARTS IN THE BORE, ONE SMALLER THAN THE OTHER AND GENERALLY CONCENTRICALLY ARRANGED WITH THE SMALL END OF BOTH IN THE SAME DIRECTION DEFINING BETWEEN THEM AN ANNULAR COMPRESSION CAVITY, AT LEAST ONE OF THE PARTS BEING FREE TO MOVE IN A DIRECTION TOWARD THE OTHER IN RESPONSE TO AN AXIAL NON-ROTARY THRUST TO REDUCE THE VOLUME OF THE COMPRESSION CAVITY TO THEREBY WEDGE AND HOLD THE STRIPPED ENDS OF ELECTRIC WIRES INSERTED IN THE COMPRESSION CAVITY, THE OUTER PART OF THE INTERFITTING PARTS BEING GENERALLY FRUSTO-CONIC AND DISPOSED IN THE CAP BORE, SMALL END TOWARD THE OPEN END OF THE CAP, WITH THE CAP CONFORMING GENERALLY TO THE EXTERIOR OF THE OUTER PART, THEREBY DEFINING A REDUCED SECTION BETWEEN THE ENDS OF THE CAP, AND A GENERALLY FRUSTO-CONIC WEDGE ELEMENT CONSTITUTING THE INNER PART DISPOSED WITHIN THE OUTER PART BETWEEN THE END WALL OF THE CAP AND THE REDUCED PORTION AND HAVING A MAXIMUM DIAMETER AT ITS LARGE END GREATER THAN THE MINIMUM DIAMETER OF THE OUTER PART AT THE REDUCED SECTION. 